Cellular bottom construction for the boat bodies of hydroairplanes



Jan. O28, 1936. H. N. A'rwooD 2,029,047

CELLULAR BOTTOM CONSTRUCTION FOR THE BOAT 'BODIES OF HYDROAIRPLANES.

Filed Sept. 14, 1934 Harry N- Hiv/00d `Patented Jan. 28, 1936 UNITED STATES PATENT OFFICE CELLULAR BOTTOM CONSTRUCTION FOR THE BOAT BODIES OF HYDROAIRPLANES Claims.

This invention relates to hydro-airplanes, and more particularly to the body thereof.

The object ofthe invention is to provide a hydro-airplane, the boat body of which is stepped 5 both longitudinally and transversely of the bottom thereof, thereby presenting a constantly decreasing water contacting surface as the speed or lifting power of the plane increases and, consequently, enabling the pilot to make a quicker vand safer take-off or landing than heretofore.

A further object of the invention is to provide a steppedv auxiliary water contacting element which may be either `built into the boat body during the fabrication thereof, or subsequently attached thereto and which may be used with equally good results on any type or style of air craft.

A further object of the invention is to provide a boat body, the bottom or water contacting surgg face of which is formed of laminated tubular members each constructed of natural wood veneer strips wound in superposed spiral layers and im pregnated with an acetone solution containing cellulosic plastic material, said tubular members being assembled in stepped relation both longitudinally and transversely of the body with their adjacent faces in intimate bonding contact with each other so as to form an integral built-up honey comb structure.

In the accompanying drawing forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the views of the drawing:

Figure 1 is a side elevation of a hydro-airplane of conventional construction, the body of which is provided with a stepped honeycomb bottom constructed in accordance with the present invention.

Figure 2 is a vertical sectional View, partly in elevation, taken on the line 2-2 of Figure 1.

Figure 3 is an enlarged detail sectional view showing the manner of assembling the tubular members.

Figure 4 is an enlarged detail sectional View showing the bonding action between the tubes.

In the accompanying drawing, I have illustrated a conventional form of hydro-airplane in which 5 designates the boat body, 6 the wings, and l the rudder, the propeller being omitted for sake of clearness. In'accordance with my invention, I propose to provide the body 5 with a stepped bottom or water contacting surface andV this stepped bottom may be built into or onto the body 5 either during the fabrication of the hydroairplane or subsequent thereto, it being understood that this stepped water contacting element may be applied to any type or style of air craft either as anintegral part thereof or as an auxiliary attachment thereto.

In carrying the invention into effect, I construct the bottom Vof the boat body of independent laminated tubular members 9 arranged side by side in superposed layers with the tubular members of each layer in bonding contact with each other and with the tubular members of adjacent layers to form an integral reinforced honey comb structure. The tubular members 9 are preferably straight throughout their entire lengths and are each formed of a strip or strips of natural wood veneer or other fibrous material impregnated with an acetone solution containing a small percentage of cellulosic plastic material such as cellulose acetate, nitrate or cellulose ester. These impregnated strips are then preferably wound in superposed spiral layers over a suitable shaping mandrel to form laminated tubes of the desired length and cross sectional shape and diameter, as fully set forth and described in my co-pending application filed in the U. S. Patent Ofce September 14, 1934 and bearing Serial No.

744,070. In fabricating the Water contacting surface of the boat body, the laminated tubes are sprayed, coated or otherwise covered with the acetone solution and While the exterior surface of the tubes are still moist or wet, said tubes are placed on suitable finishing mandrels and thenassembled to conform to the shape of a selected type or style of boat body with adjacent tubes in. intimate bonding contact with each other and the built-up structure thus formed subjected to the conjunctive action of heat and pressure. In assembling the tubular members constituting the bottom of the boat body, the tubes are preferably arranged in layers in stepped formation, that is to say, with the rear ends of the tubular members of one layer terminating short of the rear ends of the tubular members of an adjacent layer and with said layers decreasing in width toward the bottom of the water contacting element, as clearly indicated at I0 in Figure 2 of the drawing, so that the bottom of the body is stepped both longitudinally and transversely. By constructing the bottom of the boat body in this manner the effective water contacting surface of said bottom decreases in proportion to the rate of speed or lifting power of the plane, thereby offering less frictional resistance to the surface of the Water and, consequently, enabling the pilot to make a quicker and safer take-off and landing than heretofore.

By reference to Figure 4 oi" the drawing, it will be noted that the cellulosic plastic material il when subjected to heat and pressure impregnates and fills the pores and interstices of the wood veneer so as to insure an effective bond or anchorage between the parts and thus form, in effect, an integral monolithic honeycomb structure capable of resisting landing impacts, as well as tensile and torsional strains. By using cellulosic plastic material which has been dissolved in acetate to form an acetone solution, the acetate can be removed by a process of evaporation, leaving the celiulosic plastic material in its original chemical structure. Therefore, the cellulosic plastic material can be specifically applied again an-:i again, layer upon layer upon the cellulosic plastic surfaces of the tubular members or the buiit-up structure so as to cover and reinforce sai-:1 plastic surfaces with a like chemical structure and the parts Welded and integrated toget'ner into one homogeneous cellulosic piastic structure by the mere application of heat and without liability of charcoaling and carmeling the wood veneer or other fibrous reinforcing material l and, consequently, without reducing the inherent strength of said reinforcing material. Moreover, as the cellulosic4 plastic material can be softened by heat without changing its chemical characteristics, it follows that two or more of the tubular members can be chemically welded and bonded to each other and to adjacent tubular members, as well as to the surface coating' of such members, and when solidiied the plastic will form a hard glass-like surface which may `be reinforced and strengthened whenever necessary or desired by additional plastic lamina or wood and plastic iamina and heat treatments. The tubular memb-ers 9 may be secured to the boat body in any suitable manner, but it is preferred to secure said tubes' in position thereon by the bonding action previously referred to. If desired, the bank of tubular members constituting the auxiliary bottom may be coated with the acetone solution so as to be sure that all cracks and crevices are covered and also to provide an outer case-hardened protective jacket for the same.

The exposed surfaces of the outer tubular members 9 constituting the water contacting surface are preferably coated or otherwise treated with a rubber solution I2 to render the tubular members waterproof and this rubber solution is intimately combined with and bonded to the body of the tubes so as to be integral therewith and prevent scaling or peeling. Each tubular member is closed at its opposite ends and as the plastic material covers both the inside and outside of the tubes, said tubes are hermetically sealed so-that water cannotl enter the same thereby preventing deterioration of the tubes and con- `sequently prolongingthe eiective life of the .to adjacent tubular members.

ing any material structural changes therein or may be built into and as part of the boat body during the fabrication of the plane or marine craft and I do not desire to limit the invention in this respect.

Having thus described the invention, what is claimed as new is:

`1. A hydro-airplane including a boat body, and a water contacting element forming an auxiliary bottom for the boat body and constructed of hermetically sealed tubular members approximately straight throughout their entire lengths and arranged in superposed layers with the layers gradually decreasing in width toward the bottom of the contacting element to form transverse steps and with certain of the layers shorter than the others to form longitudinal steps.

2. A water contacting element for boat bodies constructed of tubular members approximately straight throughout their lengths and arranged in layers of different widths bonded together to form a transversely stepped honeycomb structure, the rear ends of the tubular members of one layer terminating short of the rear ends of the tubular members of an adjacent layer to form longitudinally disposed steps.

3. A hydro-airplane including a boat body, and a water contacting element secured to the bottom of the body and constructed of tubular members approximately straight throughout their/ entire lengths and arranged in superposed layers of different widths bonded together to form a transversely stepped honeycomb structure, the rear ends of the tubular members of one layer terminating short of the rearends of the tubular members of an adjacent layer to formV longitudinally disposed steps, said tubular members consisting of superposed plies of fibrous material covered with an acetone solution containing celiulosic material.

4. A water contacting element for boat bodies of hydro-airplanes comprising tubular members approximately straight throughout their lengths and arranged in superposed layers of different widths bonded together to forni a transversely stepped honeycomb structure, certain of the layers being shorter than others to form longitudinally disposed steps.

5. A hydro-airplane includiner a boat body having a water contacting element constructed of tubular members approximately straight throughout their entire iengths and impregnated with an acetone solution containing cellulosic plastic material, said tubular members being assembled side by side in intimate bonding contact with each other and arranged in superposed layers gradually decreasing in width toward the .bottom of the contacting element to form transversely disposed steps, certain of the layers terminating short of adjacent layers to form longitudinallyv disposed steps, and a water-prooi covering for the exposed surfaces of the tubular members intimately combined with and bonded HARRY N. ATWOOD. [L. SJ 

